Evaluating the wind cooling potential on outdoor thermal comfort in selected Iranian climate types

Abstract

Wind is one of the main factors affecting people's outdoor thermal sensation. Ongoing urbanization and urban densification are transforming the urban climate and complicating the pedestrian-level wind environment. Therefore, the main aim of this research is to evaluate the potential wind-cooling effect on human outdoor thermal conditions. Accordingly, the current research attempts determine the best wind directions for thermal comfort at the studied stations and how these factors will be changed under the effects of global warming. Outdoor thermal conditions were modeled based on the physiologically equivalent temperature (PET) thermal index using RayMan software for the decades of the 2000s and the 2040s in different climate types of Iran (Csb, BWh, Csa, and BSh) To estimate the potential cooling effect of wind, the PET was calculated (1) under actual wind conditions, and (2) under calm wind (0.05 m/s) conditions. Then, the ΔPET for these two conditions, which indicates the cooling potential effect (CPE) of the wind, was calculated for four representative stations (Ardebil, Bandar Abbas, Gorgan, and Shiraz). In comparison with the 2000s, the results indicated that by the 2040s, the predicted wind cooling potential will have increased in Ardebil, Shiraz, Bandar Abbas and Gorgan (CPE of 13.2 • C, 13.1 • C, 11.2 • C, and 11 • C, respectively). Based on the overall average of two climate change scenarios (A2 and B1) used in this study, the occurrence of "comfortable" conditions by the 2040s will have increased in Bandar Abbas, Shiraz, and Ardebil by 1.1%, 0.4%, and 0.3%, respectively, while it will have decreased in Gorgan by 1.5%. Accounting for the cooling effect of wind, the comfort cooling potential of wind is predicted to rise by an average of 1.6 • C in the 2040s compared with the 2000s in all the studied stations. Therefore, this will affect the microclimates positively and could reduce the urban heat island effects.

The case of Tehran's urban heat island, Iran: Impacts of urban ‘lockdown’ associated with the COVID-19 pandemic

“…Perhaps one of the most important spatial contexts of recent climate warming has been in large urbanized areas. Here, heat islands have expanded spatially and become more intense due to the combined effects of both regional climate warming and enhanced urban warming through increased human-induced activities and land-cover change ( Huang & Lu, 2015 ; Roshan & Moghbel, 2020a ; Roshan, Moghbel, & Attia, 2020 ). In the context of Tehran, results indicate that the heat island has expanded over recent decades, most particularly in western and southwestern sectors where this coincides with originally vegetated surfaces having changed to areas now occupied by industrial development and extensive warehouse complexes.…”

Urban Sustainability and Climate Issues: The Effect of Physical Parameters of Streetscape on the Thermal Comfort in Urban Public Spaces; Case Study: Karimkhan-e-Zand Street, Shiraz, Iran

“…They found that the urban form had a significant effect on thermal comfort. Another study by Roshan et al [35] in 2020 evaluated the effect of potential wind cooling on the outdoor thermal condition of individuals in four different climatic types of Iran. One of these climates is Shiraz with a hot and semi-arid climate.…”

Prediction of Climate Change Effect on Outdoor Thermal Comfort in Arid Region

“…Due to rapid urbanization, the global population is migrating from rural to urban areas. This change is meanly observed during the previous few decades [1]. Therefore, cityinduced climate change has serious repercussions on public outdoor activities, health and tourism.…”